Combined heating/warm water system for mobile applications

ABSTRACT

Combined heating/warm water system ( 10 ) for mobile applications, having a warm water accumulator ( 12 ) with a recess ( 14 ), and a burner ( 16 ) which is arranged in the recess ( 14 ) of the warm water accumulator ( 16 ) for the combustion of fluid and gaseous fuels, wherein the burner ( 16 ) is coupled thermally to the warm water accumulator ( 12 ) and has a combustion air supplying device ( 18 ), wherein the combustion air supplying device ( 18 ) has an air guiding apparatus ( 28 ) having an air inlet opening ( 20 ), a first air outlet opening ( 22 ) and a second air outlet opening ( 24 ), and the first air outlet opening ( 22 ) is arranged in such a way that the combustion air feeding device ( 18 ) can be cooled and the second air outlet opening ( 24 ) is arranged in such a way that combustion air can be fed to the burner ( 16 ).

The invention relates to a combined heating/warm water system for mobileapplications.

Such a combined heating/warm water system for mobile applications isknown, for example, from DE 297 22 802 U1. A burner is arranged in arecess of a warm water accumulator, the warm water accumulator beingessentially hollow-cylindrical, and the burner being essentiallycylindrical. The burner and the warm water accumulator are thermallycoupled to one another. Consequently, by means of one burner, energy canbe provided both for the heating system and for the warm water system.

It is desirable to improve further combined heating/warm water systemsof this type, in order to use them under the confined conditions ofspace, such as occur, for example, in motor vehicles, in particular inmobile homes or other camping vehicles, and also in watercraft.

The object of the invention is to provide a combined heating/warm watersystem for mobile applications, which is operationally reliable, iseasily adaptable to predetermined conditions of space and can beproduced cost-effectively.

The object is achieved by means of the features of the independentpatent claims. Advantageous developments of the invention arecharacterized in the subclaims.

The combined heating/warm water system for mobile applications isdistinguished by a warm water accumulator with a recess, and a burner,arranged in the recess of the warm water accumulator, for the combustionof liquid or gaseous fuels, the burner being thermally coupled to thewarm water accumulator and having a combustion air supply assembly, thecombustion air supply assembly having an air guide device with an airinlet port, a first air outlet port and a second air outlet port, andthe first air outlet port being arranged such that the combustion airsupply assembly can be cooled, and the second air outlet port beingarranged such that combustion air can be supplied to the burner.

The air guide device makes it possible, by means of a first airflowbetween the air inlet port and the first air outlet port, to route airthrough the combustion air supply assembly such that the latter can becooled. By means of a second airflow between the air inlet port and thesecond air outlet port, combustion air can be supplied to the burner.

It can consequently be ensured that a cooling of the combustion airsupply assembly is possible even when the heating/warm water system isat a standstill, as long as air can flow from the air inlet port to thefirst air outlet port via the combustion air supply assembly.

In an advantageous refinement of the invention, the combustion airsupply assembly has a cooling air fan. Active cooling of the combustionair supply assembly is consequently possible even when the heating/warmwater system is at a standstill. An overheating of the combustion airsupply assembly can therefore be effectively counteracted.

In a further advantageous embodiment of the invention, the combustionair supply assembly has a combustion air fan and a combustion air duct,and the combustion air duct is arranged such that the combustion air canbe supplied to the burner, with the cooling air fan being bypassed.

This makes it possible to supply the combustion air directly to theburner from the surroundings via the air inlet port, without thiscombustion air previously being warmed by parts of the combustion airsupply assembly.

In a further advantageous embodiment of the invention, the combustionair supply assembly has a combustion air fan, and the combustion air fanand the cooling air fan can be driven by a common drive device.

It is consequently possible to save a drive device for one of the fansand thus keep the outlay for the structural elements for the combustionair supply assembly low. Furthermore, it is possible to keep the energydemand for the combustion air supply assembly low.

In a further particularly advantageous embodiment of the invention, thecombustion air supply assembly has a shielding element which is arrangedon a side of the combustion air supply assembly which faces the warmwater accumulator and by means of which the thermal coupling between thecombustion air supply assembly and the warm water accumulator can bereduced.

It is consequently possible to reduce the heat flow from the warm wateraccumulator to the combustion air supply assembly by means of acomponent acting passively.

In a particularly preferred embodiment of the invention, the shieldingelement consists of aluminum. In a further particularly preferredembodiment of the invention, the shielding element consists of amagnesium/aluminum alloy. The advantage of this is that aluminum andmagnesium/aluminum alloys make it possible to have a low weight of theshielding element. Furthermore, the shielding element may bemanufactured as a casting and be connected in a simple way to othercomponents consisting of aluminum or aluminum alloys.

Exemplary embodiments of the invention are explained below by means ofthe diagrammatic drawings.

In the figures:

FIG. 1 shows a diagrammatic view of a first embodiment of the combinedheating/warm water system for mobile applications in a longitudinalsection,

FIG. 2 shows a diagrammatic view of a second embodiment of the combinedheating/warm water system for mobile applications in a longitudinalsection,

FIG. 3 shows a cross section through the combined heating/warm watersystem along the line III-III of FIG. 1, and

FIG. 4 shows a cross section through the combined heating/warm watersystem along the line IV-IV of FIG. 1.

The figures show a combined heating/warm water system 10 for mobileapplications, with a warm water accumulator 12 which has a recess 14.The warm water accumulator 12 is preferably designed as a hollowcylinder, but may also have a different geometry. A burner 16 isarranged in the recess 14 of the warm water accumulator 12. The burner16 has at its center a combustion chamber 42 and a fuel gas duct 44 isarranged coaxially around the latter. The fuel gas can be dischargedinto the surroundings via the fuel gas duct 44 and a fuel gas outletport 46.

Further, a heat exchanger 17 with heat exchanger fins 17 a is arrangedin the recess 14 of the warm water accumulator 12 between the burner 16and the warm water accumulator 12 and coaxially to these, by means ofwhich heat exchanger the burner 16 is thermally coupled to the warmwater accumulator 12. The heat exchanger 17 preferably consists ofaluminum or of an aluminum alloy. A heating medium can enter the recess14 of the warm water accumulator 12 via a heating medium inlet port 48and pass via the heat exchanger 17 having the heat exchanger fins 17 ato a heating medium outlet port 50. The heating medium is preferablyair, but may also be water, if appropriate in combination with ananti-freeze agent.

The burner 16 has a combustion air supply assembly 18 and a fuel supplyassembly 19. The combustion air supply assembly 18 has an air guidedevice 28. The air guide device 28 has an air inlet port 20, a first airoutlet port 22 and a second air outlet port 24. A cooling air fan 30 isarranged, near at least some of the air inlet ports 20, in the air guidedevice 28. By means of the cooling air fan 30, supply air 36 can beintroduced into the air guide device 28 from outside.

Further, the combustion air supply assembly 18 has a combustion air fan27, by means of which combustion air 37 can be supplied to the burner 16via a combustion air duct 26. The combustion air 37 may in this case beintroduced into the combustion air supply assembly 18 preferably eitherdirectly via the air inlet port 20 (FIG. 1) or via the air inlet port 20and the cooling air fan 30 (FIG. 2).

A further part of the airstream which is introduced into the air guidedevice 28 by the cooling air fan 30 circulates as cooling air 38preferably around the combustion air duct 26 and passes again into thesurroundings as outgoing air 39 via the first air outlet port 22.

The combustion air fan 27 and the cooling air fan 30 are preferablyarranged on a common shaft 31 which can preferably be driven by a commondrive device 32. However, the combustion air fan 27 and cooling air fan30 may also be driven by separate drive devices.

Further, the combustion air supply assembly 18 has a shielding element34. This is arranged on a side of the combustion air supply assembly 18which faces the warm water accumulator 12 and the heat exchanger 17. Theshielding element 34 preferably consists of aluminum or of amagnesium/aluminum alloy. In the shielding element 34, designed as arobust component, in particular, heat which is emitted on that side ofthe warm water accumulator 12 and of the heat exchanger 17 which facesthe combustion air supply assembly 18 can be absorbed. It isconsequently possible to cushion peak heat quantities occurring in thewarm water accumulator 12 and heat exchanger 17 such that the heatenergy cannot pass directly to the remaining regions of the combustionair supply assembly 18.

The functioning of the combined heating/warm water system 10 will beillustrated in detail below:

Supply air 36 is introduced via the air inlet port 20 into thecombustion air supply assembly 18 and is distributed there in thedirection of the first air outlet port 22 and the second air outlet port24. The combustion air 37 passing through the second air outlet port 24of the combustion air supply assembly 18 is supplied to the combustionchamber 42 by means of the combustion air fan 27. Via the fuel supplyassembly 19, preferably liquid fuel, such as is also used for drivingthe vehicle, is supplied to the combustion chamber 42 and is burnt thereby means of the combustion air 37. Instead of liquid fuel, however,gaseous fuel may also be used. The fuel gas occurring is routed outwardas exhaust gas 40 via the fuel gas duct 44 and the fuel gas outlet port46.

At the heating medium inlet port 48, a heating 16 medium, preferablyair, enters the recess 14 of the heat accumulator 12 between the heataccumulator 12 and the burner 14. The heating medium is heated in therecess 14 of the warm water accumulator 12, particularly in the regionof the heat exchanger 17 having the heat exchanger fins 17 a, andemerges from the recess 14 at the heating medium outlet port 50. Theheating medium may be supplied then by means of a heating mediumconduction system, not illustrated any further, to a heat consumer,preferably an air heating system or water heating system of a campingvehicle, a mobile home or a watercraft.

The part of the supply air 36 which is supplied to the first air outletport 22 flows as cooling air 38, in particular, around the combustionair duct 26 and the shielding element 34 and can thus cool these.

When the combined heating/warm water system 10 is inoperative and thewarm water of the warm water accumulator 12 is at a high temperature,heat can be transmitted from the warm water accumulator 12 to the heatexchanger 17 having the heat exchanger fins 17 a. Heat can then bedischarged from the warm water accumulator 12 and from the heatexchanger 17. By means of the shielding element 34, it is possible tolimit the heat flow from the warm water accumulator 12 and the heatexchanger 17 to the combustion air supply assembly 18. In particular,the shielding element 34 may be used as a buffer element for the heatenergy flowing from the heat exchanger 17 to the combustion air supplyassembly 18.

Should the temperature in the region of the combustion air supplyassembly 18 be too high, the cooling air fan 30 can be put intooperation by a suitable control arrangement and supply air 36 can berouted via the air inlet port 20 to the first air outlet port 22, thecooling air 38 being capable of cooling the combustion air supplyassembly 18. It is consequently possible by means of the cooling air fan30 and the air guide device 28 effectively to protect parts of thecombustion air supply assembly 18 which are sensitive to hightemperatures against excessively high heat load.

1. A combined heating/warm water system for mobile applications, with awarm water accumulator with a recess, and a burner, arranged in therecess of the warm water accumulator, for the combustion of liquid orgaseous fuels, the burner being thermally coupled to the warm wateraccumulator and having a combustion air supply assembly, the combustionair supply assembly having an air guide device with an air inlet port, afirst air outlet port and a second air outlet port, and the first airoutlet port being arranged such that the combustion air supply assemblycan be cooled, and the second air outlet port being arranged such thatcombustion air can be supplied to the burner.
 2. The combinedheating/warm water system of claim 1, characterized in that thecombustion air supply assembly has a cooling air fan.
 3. The combinedheating/warm water system of claim 2, characterized in that thecombustion air supply assembly has a combustion air fan and a combustionair duct, and in that the combustion air duct is arranged such that thecombustion air can be supplied to the burner, with the cooling air fanbeing bypassed.
 4. The combined heating/warm water system of claim 2,characterized in that the combustion air supply assembly has acombustion air fan, and in that the combustion air fan and the coolingair fan can be driven by a common drive device.
 5. The combinedheating/warm water system of claim 1, characterized in that thecombustion air supply assembly has a shielding element which is arrangedon a side of the combustion air supply assembly which faces the warmwater accumulator and by means of which the thermal coupling between thecombustion air supply assembly and the warm water accumulator can bereduced.
 6. The combined heating/warm water system of claim 5,characterized in that the shielding element consists of aluminum.
 7. Thecombined heating/warm water system of claim 5, characterized in that theshielding element consists of a magnesium/aluminum alloy.